A judge who granted bail to a man who went on to murder his former partner had been told the man was violent and likely to harm her, the Crown Prosecution Service (CPS) said today.

Jonathan Vass, 30, stabbed Jane Clough, a 26-year-old nurse, to death in July in a Blackpool hospital car park while on bail on charges of raping her. She had been due to give evidence against him on the rape charges when he attacked her.

Clough, mother of an infant daughter she had with Vass, was taken to the accident and emergency department at the Royal Victoria hospital, where she had been about to start her shift. Colleagues did not recognise her because of the severity of her injuries.

Judge Simon Newell said in a statement issued by the Judicial Communications Office (JCO) that he had not been told that Vass, an ambulance technician, was likely to commit further offences against his former partner.

The CPS has now said it told the judge there was an "extreme likelihood" Vass would interfere with witnesses and that Vass, of Preston, Lancashire, had committed violent crimes against his former partner.

Last month, Vass pleaded guilty to murdering Clough. The judge presiding over the murder case, Judge Anthony Russell QC, jailed him for life with a minimum tariff of 30 years. The rape charges were ordered to lie on file.

Clough's parents are angry that Vass was granted bail. "He had the power, as a judge, to remand Vass in custody and keep Jane safe," Clough's mother, Penny, said of Judge Newell.

The JCO said the judge had worked within the framework of the Bail Act 1976, which gives a presumption of bail except in specific circumstances. Bail was granted with conditions that Vass lived at a specified address; that he was not to contact his former partner, either directly or indirectly; and that he was not to enter Burnley or Pendle except to attend court or appointments with his solicitor.

"In this case, at no stage was the judge told of any concerns expressed by Ms Clough in relation to her safety, nor was there any evidence presented to the court that Mr Vass was likely to commit further offences against her," the JCO said. Vass had been of previous good character.

The CPS said it successfully opposed bail when Vass first appeared before magistrates, charged with rape, in December 2009. The defence appealed against the decision to remand him in custody at the crown court on 11 December.

"The prosecution opposed that application on the grounds that there were substantial risks that he would interfere with witnesses, particularly with Jane Clough, and a strong likelihood that he might abscond," the CPS said.

"The prosecution case put before the judge was that the defendant had been committing offences of rape and serious sexual assaults, which by their nature are violent crimes, against Jane Clough, for a number of months."